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Re: RFC: device flavours

On Thu, Jul 29, 2010 at 11:20:39AM +0300, Jukka Ruohonen wrote:
> A small note: focusing on isa(4), legacy drivers, and their configuration
> hides the real issue, which is that we need a 1:1 mapping between the normal
> and the ACPI device tree.  This is not optional if we ever want to make any
> advances for instance in PCI power management.  Another example: we have
> pending device drivers on the ACPI side that need to know about vga(4). 
> What will be there for isa(4), should be there also for pci(4).

I agree.  The issue is larger: there also has to be coordination
between, on the one side, ISA Plug 'N' Play, PCI BIOS, ACPI,
OpenFirmware, and so on; and on the other side, isa(4) i2c(4), pci(4),
et cetera.

Just for example, I'm trying to put PCI bus space under stricter control
of the kernel, and that requires coordinating the bus-space allocations
already made by PCI BIOS, for example, with allocations made by NetBSD.
On i386, device properties convey the PCI BIOS information to MI PCI
drivers.  I reckon that on sparc64, the same device properties will
derive from OpenFirmware.


David Young             OJC Technologies      Urbana, IL * (217) 278-3933

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